Stress Path Triaxial Testing System
Stress Path Triaxial Testing System
Stress Path Triaxial Testing System
Stress Path Triaxial Testing System
- Description:
Stress Path Triaxial Testing System
- Model:
Classic Bishop & Wesley Method
- Manufacturer:
APS-WILLE Geotechnik
Product Information
  • Description
  • Standard
  • Feature
  • Specification
  • Software
  • Upgrade Option
Description

This high-quality stress path triaxial system is afully automatic system consisting basically ofa Bishop & Wesley cell which controls stressdirectly on the sample, three volume pressurecontroller(VPC), internal submersible load cellto measure axial load, a pressure transducerto measure pore water pressure and a lineardisplacement transducer to measure verticaldisplacement.


Thanks to the integrated software and alsokeyboard controller (volume pressure controller),the operation of the device is very user-friendly.Exchangeable, pre-calibrated measuring sensorsguarantee high accuracy over a wide measuringrange. All the tests are running under PC controllike stress path, K0, slow cyclic and etc.

This system needs 3  volume pressurecontrollers for axial load (lower chamber), cellpressure and one for back pressure. The celland back pressure can be alternatively providedby a dual channel APC (pneumatic controller)and would be upgraded to 3 channels forunsaturated tests if required.


GEOsys software in combination with this unitperforms all your tests automatically and withoutoperator assistance during the test period. The device meets or exceeds requirements of allinternational standards; namely ASTM, BS, EN,DIN and etc which are listed at Standard sectionof this document.


General Description

Bishop and Wesley (1975) developed a simple and versatile hydraulic triaxial stress path cell, which iscalled the Bishop and Wesley cell. The hydraulic pressure inside the lower pressure-chamber appliesthe axial stress in the stress path cell. The cell chamber (upper) and the lower pressure-chamber areall sealed with belloframs and the loading ram is placed between these two chambers.

This system needs 3 Advanced volume pressure controllers for axial load (lower chamber), cellpressure and one for back pressure. The cell and back pressure can be alternatively provided by adual channel APC (pneumatic controller) and would be upgraded to 3 channels for unsaturated testsif required.

The device is equipped with advanced GEOsys software which gives the possibility to users to run allthe test stages completely automatic and there is no need pf pretense of operator during the test.


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System Geography

① Bishop and Wesley triaxial cell

② Submersible laod cell

③ Linear displacement transducer

④ Automatic Volume Pressure controller (VPC) for closed-loop control of axial stress and strain

⑤ Automatic Twin Volume Pressure controller (VPC) for cell pressure and back pressure control

⑥ Pressure transducer to measure pore water pressure and B-value check

⑦ Advanced data acquisition system for additional transducer

⑧ Software enables all kinds of stress paths and other tests


Bishop And Wesley Triaxial Cell

This cell is a Static Stress Path Hydraulic Celland does not need any conventional loadframe to supply axial stress as the verticalload is applied from lower chamber by using apiston and hydraulic pressure. The cell and thelower pressure-chamber are both sealed withbelloframs.The hydraulic pressure is suppliedby Advanced volume pressure controller.  applied load on sample depends onthe size of piston area and pressure ofthe Advanced volume pressure controller.


The hydraulic fluid is water and by controllingthe pressure inside the lower chamber bothaxial displacement and force may be controlledtherefor the accuracy of the Pressure controllermeans here.The triaxial cell is a rigid triaxial cell with an internalframe (tie-rods) to connect all submersibletransducers directly at the sample before the cellis closed by the cell-wall.

Bishop & Wesley应力路径试验系统

Single Type Volume/Pressure Controller

Automatic Electromechanical pressure volume controller is a syringe pulse-less pump which generate and regulate pressure and provide flow control in a variety range for different applications e.g. cell pressure, back pressure or air pressure for unsaturated tests.

Different modes of pressure control e.g. constant pressure, pressure ramps, constant volume flow is available with using of this pump. It has Compact and space saving design (for wall-mounting or table use) and has different modes of pressure control (e.g. constant pressure, pressure ramps, constant volume flow).

Two of these pumps generate axial hydraulic loading and back pressure and in combination with a Pore water pressure transducer and software are used to run automatically all types of required tests which are pre-programmed in software.

Bishop & Wesley应力路径试验系统

Static Controller

The MultiCon is a compact data logging system which is developed for capturing 4, 8 or 16 electronic measuring sensors with an analogue output signal (±0-10V ) and converting them into a digital measuring signal which is subsequently transmitted to a PC for storage purposes. It is a 13-bitcontrol (optional 16-bit) and data acquisition unit. This way, numerous measurement values can be captured, e.g. force, distance and pressure of static processes. 


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The measurement data is captured continuously and can simultaneously be viewed via the optional data capture software (GEOsys) and made available in ASCII format. From there, the data can be fed into any evaluation programme.

The data conversion terminal –as pictured in the example– _is used to connect up to 8 transducers(sensors with built-in preamp/measuring amplifier). 

The analogue inputs for the transducers are located on the back of the MultiCon with a supply voltage of 24 V. The inputs are for transducers with a standard signal output of ±0-10 V (optional±0-2.5 V or ±0-5 V also available).

Standard

• ASTM D-2850

• ASTM D-2850-03a

• ASTM D-4767

• ASTM D-5084

• ASTM D-7181

• ASTM D-7181-11

• BS 1377-6

• CEN ISO/TS 17892-11

• CEN ISO/TS 17892-8

• CEN ISO/TS 17892-9

Feature

• Tabletop System

• Easy sample set up and handling of the test

• Sample Size 100mm

• Different Cell pressures 2MPa / 10MPa or20Mpa

• Different Axial Loads 7kN up to 50kN

• Microprocessor-controlled precision

• Direct operation of the device by a PC withcontrolling software (communication protocolis available)

• Displacement closed-loop control usingexternal or internal displacement transducervia software

• Ethernet Port for fast data transferring to PC

• Compatible to LABVIEW©

• Submersible laod cell to measure and closedloop control of axial load with minimumfriction effects

• Real-time data and graph display

• Fully automatic adjustment of load stagesaccording to the selected stop-criteria

• Precise settlement control by using accuratedisplacement Transducer

• Fully automatic testing procedure andmonitoring via PC control, 12 devicessimultaneously and independent

Specification
Triaxial CellTechnical Specification
Sample Size/s38mm~50mm / 70mm~100 mm
Cell Pressure2 MPa /10 MPa / 20 MPa
Axial Load10kN / 25kN / 50kN
Axial Load with Motorized version50kN
Pressure Accuracy 0.1% F.S
Pressure Resolution0.1 kPa
Volume Accuracy0.1% F.S
Range of testing TemperatureOptional


Software

GEOSYS Software

GEOsys is a multi-functional and modular controlling and data acquisition software in Windows. It allows for the simple programming of complex user defined test sequences via structured Windows instructions on a graphi cuser interface.

GEOsys utilizes a flexible, programmable system that controls test appliances that coordinate various test operations. The flexible operating panel provides tools to configure the appliance, editors to carry out load procedures, and functions for analysis, presentations and logs.


The software is designed to support a modul arstructure for the test environment so as to enable a flexible configuration and thus fulfil the specific requirements of the company.

The important key feature of this software is the ability to allow users to simply and freely program standard or complex test sequences with structured Windows operations via a graphic user interface.

Thanks to the wide range of abilities Geosy soffers, it is not only compatible with our products,but it can also be used with hardware from other manufacturers, providing data acquisition and test controlling for hard- ware of a similar or more advanced standard.

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Soil Triaxial Test Modules

GEOsys is designed for closed-loop controlled static & Dynamic tests for all test applications in materialtesting, such as stress-controlled, strain-controlled, all stress paths, loops, any kind of waveforms likesine, rectangle, triangle, and predefined waves.

It is controlling and data acquisition software and also has different modules to run tests accordingto ASTM or other standard methods. Please note that some tests listed below will require optionalhardware. Depends on the requirement of the customer one or several modules would be deliveredwith main software, such as:


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• Data Acquisition, processing and devicemanagement (DPD) Module

• Saturation Module

• B-value -Test Module

• Consolidation Module (Isotropic oranisotropic)

• Permeability Test Module

• Stress path module: Linear stress paths- p, qor s, t

• Static Shear Stage Module: 

UU: Unconsolidated Undrained Triaxial Test(Total Stress test)

CU: Consolidated Undrained Triaxial Test with pore pressure measurement (Effective Stress test) 

CD: Consolidated Drained Triaxial Test with pore pressure measurement (Effective Stresstest)

• Unsaturated Test Module

• K0 Test Module

• Tension (Extension) Test Module

Upgrade Option

• Motorized Cell

The functionality of motorized cell is similar to theBishop and Wesley cell (B&W) and in this methodthe axial laod applies by a direct drive to the basepedestal of the sample through the bottom of thecell.In this method the hydraulic actuator in the lowerchamber of the B&W is replaced by this directdrive.The cell is free from top and can be lifted upfor sample set up and the drive system is easilyinterchangeable from motorized version intoHydraulic version (VPC) as well for axial load.

Bishop & Wesley应力路径试验系统

• Submersible Local Circumferential strain Measuring Device

It is used for specimen-diameter from 38 up to 100mm and includes a high accuracy Lvdt transducer and does the measurement of the average radial strain of specimen during the test.

The chain consists of a number of small chain-segments, which roll independently from eachother over the sample and can be configured for different sample sizes.

Bishop & Wesley应力路径试验系统

 Internal Axial-Deformation Measuring Device

This on sample units measures accurately the axial displacement of the sample and includes of twoLVDT transducers which are located opposite of each other and is available for sample diameters upto 100 mm. It includes of Height adjustable fixation made of stainless steel suitable for triaxial cell.


• Environmental Temperature Chamber

The cell of High-pressure Stress path Triaxial is made of steel and can be upgraded for different rangeof temperatures. This upgrade ordered before construction of cell.

This enables the user to perform the tests under variety range of temperatures from -20 ° C to +80° C(Other temperature range is available on request).Due to the PC-control of temperature unit, any kindof temperature test sequences can be performed.


• Sample Preparation Set

For each sample size, a sample preparationkit would be delivered to enable theusers to prepare sample for the test.

Sample preparation kit for is Including of: split former for non-cohesive materials, O-ring stretcher, Numbers of O-ring, suction sleeve device for cohesive materials, 100 pices of filter paper, numbers of membrane 

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• Bender Element Test

The Triaxial test system is able to simply accept bender elements and run bender element tests with its additional accessories. Piezoelectric elements can be easily placed in top and bottom cap of the device for performing bender element or compression wave velocity tests. The existing cell is initially designed to accept the Piezoelectric elements without any extra upgrading on the cell. Exchangeable Bender Element Set for any specimen from 35mm to 150 mm is available and designed for usage in Triaxial test device and can be used for other devices e.g. resonant column device, consolidation cells simple-shear or standard shear devices. Combined Bender element sets are available for Horizontal and also lateral testing for both S and P-wave testing in opposing propagation directions.

Bishop & Wesley应力路径试验系统

• Unsaturated Test Set Up

By adding additional hardware to the system, the system will be upgraded to do unsaturated testing as well. Depends on the selected method of measuring the sample volume change, the additional accessories would be different. High Air Entry Porous Bottom Disc, Advance Pressure controller (APC), unsaturated Software module are some examples of these accessories.

Bishop & Wesley应力路径试验系统

• Water De-Airing Apparatus

This compact unit provides de-aired water with low level of gas content, as it is demanded for different tests with standard volume capacity from 20 Liter up to 60 Liter.

Bishop & Wesley应力路径试验系统